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Caractérisation et valorisation des ressources en eau des bas-fonds du bassin versant du Diarha

Abstract : The Diarha watershed and its wetlands constitute hydrosystems where the agronomic, hydrological and sylvo-pastoral potentials are favorable to agricultural diversification and intensification. The characterization of all of these environments, through Remote Sensing and Geographic Information Systems, coupled with quantitative surveys, made it possible to better understand the peasant strategies implemented to enhance the potentials offered by wetland agro-ecosystems. Indeed, despite their large extensions (252 km² or 33% of the basin), the wetlands of the Diarha basin are poorly exploited: barely 14% of their area is cultivated. However, we note since the drought of 1968-1993, the increased pressure on wetlands resources, which are mainly note through the introduction of double cropping (rainy season and dry season crops) and the rush of several external actors to strengthen the resilience of farmers to food insecurity. The dynamics of wetland exploitation and the many management constraints require better knowledge of climate, its framework and hydrological functioning, which we’re tackling through a specific study calling on space science and technology and hydrological modeling. Today, advances in these fields allow an increasingly advanced understanding of the hydrological functioning of watersheds and their wetlands. The study of the climate and its framework have shown the existence of four very distinct periods which confirms on the one hand, the upward trend in rainfall between 1950 and 1967 – on the other hand, its decrease between 1968 and 1993 – the period before 1950 and since the mid-1990s are similar – surrounding the average with strong interannual variability. The resumption of rains, which began in the mid-1990s, became more pronounced during the decade 2001-2010, which marked a return of rainfall conditions to their average level. This new wet sequence is associated with an increase in extreme daily rains and the number of rainy episodes. This variability noted in rainfall produced a similar variability in runoff and agricultural yields. The results of this study suggest that climate should be taken into account for sustainable water resource management and exploitation policies (e.g., water management design, hydroelectric development and definition of appropriate adaptation strategies…) to reduce the vulnerability of ecological systems to irregular rainfall and flow variability.
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Submitted on : Tuesday, June 8, 2021 - 12:41:35 PM
Last modification on : Thursday, June 10, 2021 - 3:17:51 AM
Long-term archiving on: : Thursday, September 9, 2021 - 7:02:35 PM


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Ibrahima Thiaw. Caractérisation et valorisation des ressources en eau des bas-fonds du bassin versant du Diarha. Hydrologie. Université Cheikh Anta Diop de Dakar, 2020. Français. ⟨NNT : ⟩. ⟨tel-03253532⟩



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